Apparatus for producing coil forms



Sept. 17, 1968 (5. LLJTZ 3,401,900

APPARATUS FOR PRODUCING COIL FORMS Filed Aug. 28, 1964 2 Sheets-Sheet 1 Fig.7

1 6 72 m; PF

INVENTOR 8 Georg Lui'z Z 15 Fig. 7 W% ATTORNEYS Sept. 17, 1968 G. LUTZ 3,401,900

APPARATUS FOR PRODUCiNG COIL FORMS Filed Aug. 28, 1964 2 Sheets-Sheet 2 INVENTOR Georg Lutz ATTORNEYS United States Patent 3,401,900 APPARATUS FOR PRODUCING COIL FORMS Georg Lutz, Nuremberg, Germany, assignor to Telefunken Patentverwertungs-GmbJ-L, Ulm (Danube), Germany Filed Aug. 28, 1964, Ser. No. 392,881 Claims priority, application Germany, Nov. 12, 1963, T 25,055 14 Claims. (Cl. 24256.1)

The present invention relates to apparatus for producing coil forms from one or several foils or strips, particularly for producing condenser coil bodies.

Coiling devices are known to the prior art in which the beginning portions, or leading ends, of the foils or strips are passed through a longitudinally split coiling mandrel so that at the beginning of the coiling operation the foils are accurately held.

A process is also known, for the production of roll-type condensers, in which the beginning of a coated base layer is clamped in a slot in a coiling mandrel, the remaining foils being inserted in succession during the coiling process.

As the dimensions of coil forms and foils became increasingly smaller, it became more diflicult to clamp the beginning of the layers into a mandrel, which itself was of a very small diameter.

Therefore, foils have been coiled directly upon insulating bodies or mandrels. Great difliculties have arisen, however, in feeding the coil onto the mandrel, especially in beginning the coil. This is because thin dielectric foils, in the range of approximately 4 to 10 are often charged electrostatically by friction or unreeling, so that applying them by hand is very diflicult. An additional factor is that the foils stick to One another, because of their charge or because of the nature of the synthetic used, or they form creases or folds.

It is therefore an object of the present invention to provide an apparatus which overcomes these disadvantages, and which makes possible the automatic manufacture of coil forms.

Another object of the invention is to provide apparatus for winding coil forms, in which the leading end of the foil to be wound is guided around the coiling mandrel for about a full turn, at the beginning of the coiling operation.

It is a further object of the invention to provide a feed er, movable with respect to a coiling mandrel for pressing the leading end of a foil to be coiled against the mandrel and wrapping it therearound until the tip of the foil is in the vicinity of the standing portion of the foil whereupon a follower surface on the feeder imparts a further rotation to the mandrel to firmly tuck the tip of the foil under the standing portion thereof so that the foil is wound by the rotating mandrel.

Additional objects and advantages of the present invention will become apparentupon consideration of the following description when taken in conjunction with the accompanying drawings in which:

FIGURE 1 is a front elevational view of a device constructed in accordance with the invention.

FIGURE 2 is a similar view of the device, shown with the feeder in an inwardly pivoted position.

FIGURE 3 is a similar view of the device, shown with the feeder pivoted inwardly, near the end of a feeding operation.

FIGURE 4 is a view similar to those of FIGURES l to 3, wherein the feeder is shown in an outwardly pivoted position having just been released from the mandrel.

FIGURE 5 is a front elevational view illustrating a different embodiment of, and method of using, the device.

FIGURE 6 is a side elevational view, in partial section, illustrating another embodiment of the device.

FIGURE 7 is a side elevational view, in partial section, illustrating still a further embodiment of the invention.

Reference numeral 1 designates a coiling mandrel, which is preferably longitudinally rifled, or grooved, and about the axis of which a feeder 3, pivotally mounted about a center of rotation 2, is provided, for example on a disc 4. I

The feeder 3 has a gripper 5, the inner configuration of which corresponds to the circumference of the coiling mandrel. The centerpoint of the hook-shaped portion of gripper 5 coincides with that of the coiling mandrel 1 when the feeder 3 is pivoted against the coiling mandrel. Preferably, the hook-shaped portion of gripper 5 may extend around the coiling mandrel 1 for approximately half the circumference of the latter.

The gripper is fashioned to be very thin at its tip 6, and may taper at a very acute angle therefrom. The end 7 of the gripper, which serves as a follower surface, is extended and formed so as to be resilient. It is bent or formed in such a manner that it can slide by the coiling mandrel 1 when the feeder is pivoted toward the mandrel, and such that when the mandrel is rotating in a clockwise direction, the feeder 3 can be smoothly pivoted outwardly again due to the friction force between the rotating mandrel 1 and gripper end 7.

The feeder may be held in its outwardly-pivoted position by a soft spring or by means of some other suitable mechanism. The gripper 5 can be a flat keeper spring, which is fastened to the feeder 3.

A stop pin 8 is provided on the feeder 3 which can cooperate, in the rest position (shown by FIGURE 1) with a stop 9 and, in the position where the gripper is next to the mandrel, with an end stop 10.

The mode of operation of the device is as follows:

In the rest position (FIGURE 1), the stop pin 8 contacts stop 9, the feeder being in its outwardly-pivoted position. One or several dielectric and/ or metallic foil(s) 11 are placed into the space between gripper 5 and coiling mandrel 1. If, now, the feeder 3 is pivoted toward the coiling mandrel 1, the foil 11 is gripped by the gripper 5 and pressed against the coiling mandrel 1, as shown by FIGURE 2. It is advantageous to push the foil 11 in so far that its end projects beyond the gripper tip 6.

Next, the feeder 3 (and its pivot 2) is rotated about the centerpoint of the coiling mandrel 1. This may be accomplished by rotating the mandrel clockwise, whereupon the friction between the gripper 5, foil 11, and coiling mandrel 1 will cause the feeder to rotate along with the mandrel, or a separate mechanical means may be utilized, as will be explained in greater detail later. In the embodiment shown here, it may be done by rotating the disc 4. During this operation, the end of foil 11 extending beyond the gripper tip 6 is folded over the gripper tip 6 and is carried into the cleft between coiling mandrel 1 and the standing portion of foil 11 as shown in FIGURE 3. By further rotating the coiling mandrel 1 is a clockwise direction, the beginning of the foil is wrapped; at the same time, the gripper 5 presses the foil 11 against the coiling mandrel 1, the arriving foil 11 being pulled into the coil.

In the meantime, the stop pin 8 has engaged the end stop 10, so that the gripper 5 is pivoted away from the coiling mandrel 1. In this position, the disc 4 is arrested.

Because of the resilient construction of the gripper end 7, the foil 11 continues to be pressed against the coiling mandrel 1 while stop 10 is causing the feeder 3 to return to its outwardly-pivoted position (FIGURE 4), on account of the friction force between foil 11 and gripper end 7.

After the feeder 3 has been pivoted outwardly, the disc 4 rotates in counterclockwise direction, returning the feeder to its start position, while the coil form is being wound.

In the production of condenser coil bodies, the conductive foil(s) and the second dielectric foil are placed upon the arriving foil 11, preferably after the first few turns, and are then coiled together with foil 11. However, it is also possible to simultaneously coil several foils. Paper, plastic materials, or the like may be used as the dielectric foils. In the manufacture of condensers, foils which are metallized on one side or on both sides and which are made of paper and/or lacquer and/or plastic may also be used.

The coiling mandrel 1 may be fixedly mounted to the device, in which case the coil form is pulled off after the winding operation is finished. However, a coiling mandrel may also be provided which remains inside the coil form after it is finished. Preferably, in the latter case, the coiling mandrel is made of insulating material, for example, ceramic material or a suitable plastic.

A further advantageous development of the invention is illustrated in FIGURE 5. Here, the gripper tip 6 is fashioned as a tear-off edge, for example, by sharpening and/or serrating the edge. This makes it possible, in a single operating step, to remove the finished coil from the coiling device, to newly insert the foil, and to cut off the finished coil at the same time.

This operation takes place as follows:

First, a coil form is produced as described with reference to FIGURES 1 to 4. After the start of this coil form has been fed to the device and after the first several turns, the feeder 3 pivots back into its starting position shown in FIGURE 1. When the coil form is finished, it is removed from the coiling mandrel 1 by hand or by a mechanical means, or the coiling mandrel is cut off and remains within the coil form. Then, the coil form is moved in the direction indicated by the standing portion of the foil 11 in such a manner that the foil 11 is positioned between feeder 3 and the coiling mandrel 1.

If, now, the foil 11 is gripped by the gripper and is pressed against the coiling mandrel 1 for producing the next coil form, the foil can be cut ofi at the gripper tip 6 by a light pull or a short jerk at the coil form which had already been finished.

A particularly simple and suitable device, illustrative of the invention, is shown in FIGURE 6. Here, the coiling mandrel 1 is axially movable in a coiling shaft 12, and is mounted so as to he rotatable therewith. The disc 4 carrying the feeder 3 is positioned on the coiling shaft 12, in such a manner that, because of the way the bearing play is selected, a moment of rotation effective at right angles to the plane of the disc in the direction of arrow 13 leads to a tilting of the disc 4 on the coiling shaft 12; this results in a friction contact between the two. No such bearing play is present between mandrel 1 and shaft 12.

The feeder 3 with gripper 5 is arranged such that, when feeding, the coiling mandrel 1 can exert a force upon the feeder 3 and its shaft 2 in the direction of arrow 14.

The operation of this device is as follows:

The device is initially in the position shown in FIG- URE 1. By causing the pin 8 to contact the stop 9, for example by briefly rotating the disc 4 in counterclockwise direction, the feeder 3 is brought into operating position.

As soon as the gripper 5 engages the coiling mandrel 1, which is preferably alneady rotating, the mandrel 1 exerts a force on the gripper in the direction of arrow 14 (FIGURE 6). This causes the disc 4 to be tilted and carried along by friction contact when the coiling shaft 12 rotates. Because of this, the feeder is brought into the position shown in FIGURE 3. At the time the stop pin 4 8 cooperates with the end stop 10, the follower surface of the gripper end 7 travels along the coiling mandrel 1. Once it has ended its travel along the mandrel, so that the end of the follower 7 does not contact the coiling mandrel any more, the force 14 vanishes and the moment of rotation 13 is eliminated, allowing the dsic 4 to assume the position shown in FIGURE 1, preferably due to gravity acting on feeder 3. In addition, the feeder 3 is returned to its starting position by means of spring 15.

Another suitable and simple means of coupling the disc 4, or an arm provided in place of this disc, shown in FIGURE 7, involves fixedly connecting a coupling member 16 with the shaft 2. The end surface of the coupling member can press against the coiling shaft 12 as long as the gripper 5 is in frictional contact with the coiling mandrel 1; when the gripper 5 is moved away from the mandrel, the coupling member disengages from the shaft so that the gripper no longer turns with the mandrel 1.

The invention thus provides a device in which the foil is always safely gripped, and creases occurring because of oblique feeding, as often happens when the process is carried out manually, are completely avoided. Furthermore, during a coiling operation as taught by the invention, the number of turns (especially in the case of condensers, the first few turns of insulating layer) can be accurately counted, as the start and the engagement of the foil always occur at precisely defined places.

It will be understood that the above description of the present invention is susceptible to various modifications, changes and adaptations, and the same are intended to be comprehended within the meaning and range of equivalents of the appended claims.

What is claimed is:

1. Apparatus for producing coil forms of one or more foils, comprising, in combination:

a coiling mandrel for coiling a foil;

feeder means movable with respect to the coiling mandrel for pressing the leading end of a foil to be coiled against said mandrel and wrapping it therearound until the tip of the foil is in the vicinity of the standing portion of the foil, said feeder means including a gripper fashioned to correspond to the circumference of the coiling mandrel and extending approximately half way around said circumference, and a follower surface for resiliently pressing against the coiling mandrel during removal of the feeder means therefrom, the gripper having a thin tip on its end opposite the follower surface;

mounting means rotatable about the axis of the coiling mandrel; and

means pivotally connecting the feeder means to said mounting means at a point displaced from said axis, a stop pin for actuating the feeder means, a first stop member for contacting the stop pin in a starting position, and a second stop member for contacting the stop pin in a finishing position, wherein the feeder means has wrapped the foil :around the mandrel so that the foil tip is in the vicinity of the standing portion of the foil.

2. Apparatus as defined in claim 1, wherein the mandrel is provided with axially extending rifiing.

3. Apparatus as defined in claim 2, wherein the gripper tip includes means for tearing off a foil pulled against it.

4. Apparatus as defined in claim 1, including a coiling shaft for rotating the mandrel, and means attaching the mounting means to the coiling shaft for producing a friction contact between the shaft and the mounting means when the latter is tilted with respect to the shaft.

5. Apparatus as defined in claim 4, wherein the engagement of the feeder means with the coiling mandrel causes the mounting means to tilt with respect to the shaft, and this disengagement of the feeder means causes the mounting means to assume its original position.

6. Apparatus as defined in claim 5, further including spring means for holding the feeder means away from the mandrel.

7. Apparatus for producing coil forms of one or more foils, comprising, in combination:

a coiling mandrel for coiling a foil;

feeder means having a gripper partially surrounding the mandrel so that the gripper presses a length of foil corresponding to the reach of the gripper against the mandrel when the gripper is placed against the mandrel;

mounting means rotatable about the axis of the coiling mandrel; means pivotally connecting the feeder means to said mounting means at a point displaced from said axis to provide a center of rotation which itself can be circularly rotated about the coiling mandrel; and

stop means arranged to contact the feeder means for placing the feeder means in operating position and arranged to contact the feeder means for placing the feeder means out of operation when the axis of the feeder means has rotated around the coiling mandrel to the point where the tip of the gripper is in the region of the foil to be coiled.

8. Apparatus as defined in claim 7 wherein said gripper includes a follower surface for pressing against the coiling mandrel during removal of the feeder means and thus pressing the foil against the mandrel.

9. Apparatus as defined in claim 7 wherein the mandrel is provided with axially extending rifiing.

10. Apparatus as defined in claim 9 wherein the tip of the gripper includes means for tearing olf a foil pulled against it.

11. Apparatus as defined in claim 7 including a coiling shaft for rotating the mandrel, and means attaching the mounting means to the coiling shaft for producing a friction contact between the shaft and the mounting means when the latter is tilted with respect to the shaft.

12. Apparatus as defined in claim 11 wherein the engagement of the feeder means with the coiling mandrel causes the mounting means to tilt with respect to the shaft, and this disengagement of the feeder means causes the mounting means to assume its original position.

13. Apparatus as defined in claim 12 further including spring means for holding the feeder means away from the mandrel.

14. Apparatus as defined in claim 7 wherein said stop means includes a stop pin for actuating the feeder means, a first stop member for contacting the stop pin in a starting position, and a second stop member for contacting the stop pin in a finishing position, wherein the feeder means has wrapped the foil around the mandrel so that the foil tip is in the vicinity of the standing portion of the foil.

References Cited UNITED STATES PATENTS 2,361,264 10/1944 Christman 24264 X 2,668,675 2/1954 Wolfe 24256 2,789,774 4/1957 Petersen et al. 24218 2,950,873 8/1960 Nelson 24256 3,062,465 11/1962 Hunter 24256 GEORGE F. MAUTZ, Primary Examiner. 

1. APPARATUS FOR PRODUCING COIL FORMS OF ONE OR MORE FOILS, COMPRISING, IN COMBINATION: A COILING MANDREL FOR COILING A FOIL; FEEDER MEANS MOVABLE WITH RESPECT TO THE COILING MANDREL FOR PRESSING THE LEADING END OF A FOIL TO BE COILED AGAINST SAID MANDREL AND WRAPPING IT THEREAROUND UNTIL THE TIP OF THE FOIL IS IN THE VICINITY OF THE STANDING PORTION OF THE FOIL, SAID FEEDER MEANS INCLUDING A GRIPPER FASHIONED TO CORRESPOND TO THE CIRCUMFERENCE OF THE COILING MANDREL AND EXTENDING APPROXIMATELY HALF WAY AROUND SAID CIRCUMFERENCE, AND A FOLLOWER SURFACE FOR RESILIENTLY PRESSING AGAINST THE COILING MANDREL DURING REMOVAL OF THE FEEDER MEANS THEREFROM, THE GRIPPER HAVING A THIN TIP ON ITS END OPPOSITE THE FOLLOWER SURFACE; MOUNTING MEANS ROTATABLE ABOUT THE AXIS OF THE COILING MANDREL; AND MEANS PIVOTALLY CONNECTING THE FEEDER MEANS TO SAID MOUNTING MEANS AT A POINT DISPLACED FROM SAID AXIS, A STOP PIN FOR ACTUATING THE FEEDER MEANS, A FIRST STOP MEMBER FOR CONTACTING THE STOP PIN IN A STARTING POSITION, AND A SECOND STOP MEMBER FOR CONTACTING THE STOP PIN IN A FINISHING POSITION, WHEREIN THE FEEDER MEANS HAS WRAPPED THE FOIL AROUND THE MANDREL SO THAT THE FOIL TIP IS IN THE VICINITY OF THE STANDING PORTION OF THE FOIL. 